Abstract
Disruptive body coloration is a primary camouflage tactic of cuttlefish. Because rapid changeable coloration of cephalopods is guided visually, we can present different visual backgrounds (e.g., computer-generated, 2-dimensional prints) and video record the animal's response by describing and grading its body pattern. We showed previously that certain aspects of size, contrast, and number of light squares on a checkerboard background elicit disruptive coloration in cuttlefish. Here we test some of the complex interactions among key background features such as size, contrast, overall intensity, and context (or configuration). A key finding is that contrast (measured as Weber contrast) has a strong influence on evoking disruptive coloration, even over large variations in size of the light objects on a dark surround (shown previously to be the central basic stimulus). Moreover, for fixed light object Weber contrast, disruptive responding decreases with increasing background mean luminance. This study highlights the complex interactions of multiple features of visual backgrounds that directly influence the choice of camouflage pattern that a cuttlefish will choose as it encounters different visual microhabitats in the natural environment.
Support: National Science Council of Taiwan, NSC-95-2621-B-007-001-MY3